When it comes to pressure, state Rep. Chuck Gatschenberger, R-Lake St. Louis, asserted, "On a scale of 1-10, this is probably an 8 or 9."

Gatschenberger is among the 19 Republicans who voted against the proposal. Gatschenberger, who is running for the state Senate this fall, said he plans to stick with his stance -- despite pressure to switch his vote, or skip the next roll call.

Credit Bill Greenblatt | UPI

Tim Jones

Credit File photo

The four votes that Jones needs must come from the 19 GOP legislators who cast “no” votes last week or the 11 Republicans who didn’t vote at all.

The absentees included state state Rep. Rick Stream, R-Kirkwood, who told the Associated Press that he intentionally skipped last Wednesday's roll call vote. He implied that he feared that any vote he cast could threaten his bid for St. Louis County executive since the county is generally deemed pro-union turf.

Under “right to work,’’ unions and employers would be barred from requiring all workers to pay dues or fees if a majority votes to join a union. "Right-to-work" backers say their proposal would guarantee workers' freedom, while opponents say the real aim is to choke off union finances because unions often back Democratic candidates.

Jones, who is expected to seek a statewide office in 2016, has made clear for months that one of his key goals this session is to win passage of "right to work,'' a favorite issue for many national conservative groups.

Some Republicans have alleged that some advocates have promised money-raising help to reluctant legislators. Gatschenberger said the offers have "not been overt'' in order to avoid violating the law.

Jones oversaw a caucus meeting late Monday of the chamber’s 108 Republicans in a bid to snag the necessary four additional votes. Several allies privately said in interviews that it was unclear whether they had succeeded.

Labor supporters have been active as well in an effort to keep any new vote count below the needed 82.

Backers have until this legislative session ends in mid-May to conduct new votes on the proposal, but all sides say that any realistic attempt to get “right to work’’ on the August or November ballot would require action within the next couple weeks to give Senate supporters time to amass their votes.

The bid to put the proposal on the ballot appears aimed at skirting Gov. Jay Nixon, a Democrat who has pledged to veto any measure that would put “right to work” in effect. The General Assembly doesn’t need Nixon’s support to place a proposal on a statewide ballot.